4. in another large clean bowl, beat egg whites until stiff peaks form.

5. fold 1/3 of the whites into batter to lighten it, then fold in remaining egg whites.

6. fill the cupcake liners about 3/4 full.
bake for 20 minutes, or until a toothpick inserted into the cake comes out clean.
let cool completely.

7. meanwhile, with an electric mixer, beat together sugar and butter.
mix on low until well blended, and then on medium for another two minutes.
add vanilla and champagne, beating on medium for another minute.